In the field of lighting, many different types of light sources have been developed for illumination purposes. Depending on application, each type of light source may have specific advantages and disadvantages. In any case each type of light source has particular specifications, and power sources (or drivers) for such light sources have been developed for meeting the particular specifications.
A recent development is the high-power LED as light source for illumination purposes. While of course drivers for illumination devices utilizing LEDs as light sources have been and are being developed, there is also a desire to utilize LEDs as replacement for the light sources in existing illumination devices (retrofit), in which case the electrical input signal to the lamp is generated by an existing driver adapted for meeting the particular specifications of the existing (non-LED) light source. This leads to several problems and/or difficulties.